Improved the performance of the harmonization matching strategy

1. cleaned up the code a bit and deleted some lame functions. Created Class in Java class in order to use Gson method.
2. improved the matching performance quite a lot.
3. simplified the UI and information can be rendered in an elegant way.
4. added new function that it is now possible to match a predictor ONLY against biobank variables. 
5. There are a lot files changed, however they are all related to harmonization ONLY, will not affect other`s applications